Turbine engines, and particularly gas turbine engines, also known as combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of turbine blades. Gas turbine engines have been used for land and nautical locomotion and power generation, but are most commonly used for aeronautical applications such as for airplanes. In airplanes, gas turbine engines are used for propulsion of the aircraft.
The engine is attached to a wing by a pylon, typically a metal arm that joins the engine to the wing or fuselage of the aircraft. Through pumps and feed tubes in the pylons, fuel is relayed from wing tanks to the engine. Additionally, electrical power generated by the engine, as well as hydraulic lines and air management system ducts, control system wiring, etc. are routed between the aircraft and engine through wires and piping also contained in the pylons. The engine is contained within external casings, called cowls. These cowls typically form the inner wall of a fan duct on aircraft applications. These engine cowls are supported in part by the pylon and in part by the engine.
Conventional cowl arrangements include the inner and outer cowls that are structurally attached to each other via bifurcation walls and beams that permit hinged opening and closing of the cowls for engine access, and in some cases permit sliding of the outer cowl for thrust reverser operations. In other arrangements the inner cowl remains independent from the outer cowl (i.e. has no direct structural attachment between the cowls). In this case the inner cowling covers the jet engine and has either a fixed frame structure with many access panels to provide engine access or hinged opening forward doors with a sliding aft cowl section that may be moved to provide access for maintenance of the jet engine.